This proxy release changes the multicluster gateway to discover Gateway
API routes via the `OutboundPolicy` API. This builds on the similar
changes to the outbound proxy in v2.192.

---

* gateway: discover client policies from the policy controller (linkerd/linkerd2-proxy#2315)
* build(deps): bump windows_x86_64_msvc from 0.42.1 to 0.42.2 (linkerd/linkerd2-proxy#2319)
* build(deps): bump proc-macro2 from 1.0.51 to 1.0.52 (linkerd/linkerd2-proxy#2320)
* outbound: Apply filters to outbound requests (linkerd/linkerd2-proxy#2260)
* test: add mock client policy resolver (linkerd/linkerd2-proxy#2314)
* build(deps): bump tj-actions/changed-files from 35.6.4 to 35.7.0 (linkerd/linkerd2-proxy#2318)
* build(deps): bump axum from 0.6.10 to 0.6.11 (linkerd/linkerd2-proxy#2321)
* build(deps): bump ryu from 1.0.12 to 1.0.13 (linkerd/linkerd2-proxy#2322)
* build(deps): bump windows_x86_64_gnullvm from 0.42.1 to 0.42.2 (linkerd/linkerd2-proxy#2323)
* outbound: Eagerly cancel synthesized profile task (linkerd/linkerd2-proxy#2317)
* outbound: Simplify discovery debug logging (linkerd/linkerd2-proxy#2316)
* build(deps): bump tj-actions/changed-files from 35.6.1 to 35.6.4 (linkerd/linkerd2-proxy#2309)

* outbound: fix `Balance::Dispatch` "authority" labels (linkerd/linkerd2-proxy#2332)
* outbound: refactor `discover::resolver` into a method (linkerd/linkerd2-proxy#2331)

Both outbound and gateway proxies now resolve client policies from the
OutboundPolicies API. When the outbound proxy attempts to discover a
policy and the policy controller returns NotFound, it synthesizes a
default policy from the discovered ServiceProfile. However, when the
gateway proxy receives a NotFound, it will currently fail the
connection, based on the assumption that only valid cluster DNS names
are gatewayed (and not arbitrary IPs that might be forwards).
Unfortunately, this is not quite true. Gateway proxies may attempt to
discover cluster DNS names that are Pod DNS names, rather than Service
DNS names, and the policy controller will return NotFound for those
names.

This branch therefore changes the gateway proxy to also synthesize
default ClientPolicies based on the ServiceProfile when receiving a
NotFound status. Some of the code for synthesizing a client policy
from a ServiceProfile that's currently used in the outbound proxy was
factored out so that it could be reused here.

---

* gateway: move discovery resolver into its own file (linkerd/linkerd2-proxy#2343)
* outbound: Fix incorrect l5d-proxy-connection logs (linkerd/linkerd2-proxy#2344)
* gateway: synthesize ClientPolicies when the controller returns `NotFound` (linkerd/linkerd2-proxy#2333)

Signed-off-by: Oliver Gould <ver@buoyant.io>